Printing machine impression mechanism



Jan. 7, 1958 c. A. HARLESS PRINTING MACHINE IMPRESSION MECHANISM FiledFeb. 15, 1956 IINVENTOR 5/ United States Patent PRINTING MACHINEIMPRESSION MECHANISM Charlestm-Harless, Riverside, Conm, assignor to R.Hoe & go klnca New York, N. Y., a corporation of New ApplicationFebruary 15, 1956, Serial'No. 565,630

8; Claims (.CL. 101--247) This invention relates to printing machineimpression mechanism, and more particularly to such mechanism forapplying, printing, pressure through the bearings and shaft supportingone of a. pair ofi cooperating printing cylinders. While applicablegenerally, the invention is of particular importance in magazine pressesor other presses in which the cylinders have rigid metal bearer rings.In machines of the type indicated, there: is a. tendency fordifferential expansion. or contraction of the press frames as comparedwith. the bearer rings to cause considerable change in pressure of. thebearer rings against each other as the press operates. Also, since thebearers are rigid elements, a very small change in distance between theaxes of the cooperating cylinders canv produce a disproportionate andextremely large increase in pressure. It is, therefore, desirable toprovide some means for adjusting the axial distance between cylindersslightly to compensate for thermal effects and thus maintainsubstantially predetermined bearer ring pressure, and it is alsodesirable to provide a means for throwing on the impression which willnot require an accurate setting of parts by the press operator. As willbe apparent, similar problems, although not quite so severe, areencountered even in the absence of bearer rings due to differentialexpansion as between the frames and cylinder bodies themselves;

Hydraulic devices in which the hydraulic cylinder exerts pressurethrough a piston on a cylinder bearing have been proposed, but thesedevices involve the use of a good deal of piping and giverise tootherdifliculties not found in mechanical constructions. Spring pressedelements have, in general, not been useabl'e' for the purpose indicatedbecause, where a resilient element such as a spring is interposedbetween anop'erat'ing member and a bearing, the initial retractingmovement of the operating member in throwing off the" impressioninvolves an expansion of a spring and the engagement of a stop orlimiting member may take place witha certain amount of impact.

A general object of the present invention is to provide a resilientimpression mechanism for maintaining constant bearing pressure, whichwill not require close adjustment and which permits throwing ofi theimpression with substantially no lost motion and substantially no'impact between parts.

2,818,804 Patented Jan. 7, 1958 Fig. l is a schematic end elevation of amachine embodying the invention in a preferred form;

Fig. 2 is an enlarged elevational view of part of Fig. 1, showing thespring and hydraulic connecting link in axial section; and

Fig. 3 is a plan View of the mechanism of Fig. 2.

In Fig. 1 there is indicated in phantom a plate cylinder 10 andcooperating impression cylinder 11, together with a frame structure 12for rotatably supporting the impression cylinder 11 and supporting theplate cylinder 10 by means of an eccentric ring 14 within which itspositioned the plate cylinder bearing 15.

The eccentric bushing 14 has a fork 16, within which one end of a link17 is pivotally connected by pin 18 and the opposite end of link 17 ispivotally connected by means of a pin 19 in a fork 20 at one end of acrank arm 21 carried on shaft 22. By rotating crank arm 21 about theaxis of shaft 22 (clockwise in Fig. 2) the impression may be thrown ofl,eccentric bushing 14 being rotated clockwise thereby from the positionof Fig. 2 where the link and crank arm are lined up and substantially ondead center, and impression pressure is applied.

The link 17 comprises a cylinder 25 within which is mounted a piston 26carried by a piston rod 27, to which it is secured by a pin 23. Withincylinder 25 and thrusting against the piston 26 is positioned acompression spring 28. The end 29 of piston rod 27 is received Within anauxiliary cylinder bore 30, the cylinder wall 31 surrounding whichserves to maintain the spring 28 in alignment, the other end of thespring being received in an annular recess 32 within the piston. Thepiston rod 27 has a central bore 33 communicating through a crosschannel 34 with hydraulic working space 35 at one end of the piston andcommunicating through a ball check valve 36 with the space Within bore30, which, in turn, communicates with the space 37 within the cylinder25 through a port 38. A helical groove 40 in the piston surfacesprovides a restricted passage for leakage of oil across the piston fromspace 35 to space 37. Oil is maintained at substantially normal orstatic pressure within the cylinder 25 by means of a reservoir cylinder41 having a Working space 42 communicating through the passage 43 withthe space 37, and having a piston 44 to which pressure is applied by aspring 45 Starting with the parts in the position of Figure 2, when theimpression is to be thrown oflF, shaft 22 is rotated rapidly in theclockwise direction, pulling cylinder 25 to the right and exertingpressure through the hydraulic fiuid in space 35 against piston 26. Theoil groove 40 being relatively small, and the check valve 36 beingclosed, practically no oil can flow past the piston, and, accordingly,piston rod 27 moves with cylinder 25 practically as a rigid unit. If theimpression remains otf, spring 28 will gradually expand until piston 26comes against the cylinder head, substantially eliminating the workingspace 35. This motion will be slow, as the leakage across the pistonmust pass through the groove 40. When the impression is reapplied, thepiston and cylinder may occupy the relative position shown in the figureor the piston 26 may then push against the cylinder end wall, or thepiston may be in any intermediate position, without substantial effectupon the operation of the device. In any event, as the parts arereturned to the dead center position: of the figure, piston 26, if notalready pushed intow the. cylinder 25, will be pushed into the same tothe required: extent to apply the impression pressure which will bedetermined by the spring compression and the mechanical. advantage ofthe spring over the impression. cylinder bearing.

Adjustment-- for variation. in. thickness of packing of cylindersor forany other desired reason is provided for 3 and comprises means forshifting the pin 19, so as to vary the position of the pivotal axis oflink 17 and crank arm 21. Pin 19 is journaled in the fork 20 but is notjournaled directly in the end of link 21. Instead, it carries aneccentric bushing 19' fixed to it by a key H so that turning the shaftor pin 19 varies the effective length of link 17. The element 19 mayconveniently be turned as by means of a pin wrench, and is releasablylocked in position by a bar 46 recessed to one side to fit the shaft 19,and slidably carried in a bore 47 in the fork 2%. A nut 48 on the outerscrew threaded end or" the bar 46 serves to lock and unlock the pin 19,as tightning up on the nut 48 and exerting tension on bar 46 will applya wedging action against the pin 19, preventing its rotation.

The equipment normally requires little or no servicing. The oil may bechanged or replenished when necessary through any suitable opening, asfor example, through a port 49 in the auxiliary cylinder 41, which portis normally plugged.

What is claimed is:

1. In a printing machine having a pair of cooperating printing cyindersand a support for one of said cylinders movably mounted for movement inone direction to increase impression pressure and in the other to throwoff the impression, the combination with the said support of anoperating mechanism comprising cooperating hydraulic cylinder and pistonelements defining a working space, and a spring for applying impressionpressure and acting between said piston and cylinder in a direction toreduce said working space, a crank, and means connecting one of the saidhydraulic elements to the support and the other to the crank, the lastsaid means being positioned so that the spring acts to force thecylinder carried by the said support in the first said direction.

2. In a printing machine having a pair of cooperating printing cylindersand a support for one of said cylinders movably mounted for movement inone direction to increase impression pressure and in the other to throwoi the impression, the combination with the said support of an operatingmechanism comprising cooperating hydraulic cylinder and piston elementsdefining a working space and having a restricted channel for flow out ofthe working space, and a spring for applying impression pressure andacting between said piston and cylinder in a direction to reduce saidworking space, a crank, and means connecting one of the said hydraulicelements to the support and the other to the crank, the last said meansbeing positioned so that the spring acts to force the cylinder carriedby the said support in the first said direction.

3. In a printing machine having a pair of cooperating printing cylindersand a support for one of said cylinders movably mounted for movement inone direction to increase impression pressure and in the other to throwoff the impression, the combination with the said support of anoperating mechanism comprising cooperating hydraulic cylinder and pistonelements defining a working space, a check valve for permitting flowacross said piston into the said working space while preventing flow outof said working space, and a spring for applying impression pressure andacting between said piston and cylinder in a direction to reduce saidworking space, a crank, and means connecting one of the said hydraulicelements to the support and the other to the crank, the last said meansbeing positioned so that the spring acts to force the cylinder carriedby the said support in the first said direction.

4. In a printing machine having a pair of cooperating printing cylindersand a support for one of said cylinders movably mounted for movement inone direction to increase impression pressure and in the other to throwoff the impression, the combination with the said support of anoperating mechanism comprising cooperating hydraulic cylinder and pistonelements defining a working space, a check valve for permitting flowacross said piston into the said working space while preventing flow outof said Working space, a restricted channel for flow across said pistonout of said working space, and a spring for applying impression pressureand acting between said piston and cylinder in a direction to reducesaid working space, a crank, and means connecting one of the saidhydraulic elements to the support and the other to the crank, wherebythe said hydraulic elements act as a substantially rigid link when thecrank is turned to throw ofi the impression and the said support is heldin impression applying position by the resilient action of the saidspring, the last said means being positioned so that the spring acts toforce the cylinder carried by the said support in the first saiddirection.

5. In a printing machine having a pair of cooperating printing cylindersand an eccentric bushing for one of said cylinders rotatively mountedfor movement in one direction to increase impression pressure and in theother to throw oit the impression, the combination with the said bushingof an operating mechanism comprising coopcrating hydraulic cylinder andpiston elements defining a working space, and a spring for applyingimpression pressure and acting between said piston and cylinder in adirection to reduce said working space, a crank, and means connectingone of the said hydraulic elements to the bushing and the other to thecrank, the crank being positioned so as to be on dead center inimpression applying position, and the said means connecting thehydraulic elements to the bushing being arranged so that the spring actsto turn the eccentric bushing in a direction to increase impressionpressure.

6. In a printing machine having a pair of cooperating printing cylindersand an eccentric bushing for one of said cylinders rotatively mountedfor movement in one direction to increase impression pressure and in theother to throw ofi the impression, the combination with the said bushingof an operating mechanism comprising cooperating hydraulic cylinder andpiston elements defining a working space, and a spring for applyingimpression pressure and acting between said piston and cylinder in adirection to reduce said working space, a crank, means connecting one ofthe said hydraulic elements to the bushing and the other to the crank,the crank being positioned so as to be on dead center in impressionapplying position, one of the said connecting means being adjustable forvarying the length of the working space when the crank is on deadcenter, and the said means connecting the hydraulic elements to thebushing being arranged so that the spring acts to turn the eccentricbushing in a direction to increase impression pressure.

7. In a printing machine having a pair of cooperating printing cylindersand an eccentric bushing for on e of said cylinders rotatively mountedfor movement in one direction to increase impression pressure and in theother to throw off the impression, the combination with the said bushingof an operating mechanism comprising cooperating hydranlic cylinder andpiston elements defining a working space, a check valve for permittingflow across said piston into the said working space while preventingflow out of said working space, and a spring for applying impressionpressure and acting between said piston and cylinder in a direction toreduce said Working space, a crank, and means connecting one of the saidhydraulic elements to the bushing and the other to the crank, the crankbeing positioned so as to be on dead center in impression applyingposition, and the said means connecting the hydraulic elements to thebushing being arranged so that the spring acts to turn the eccentricbushing in a direction to increase impression pressure.

8. In a printing machine having a pair of cooperating printing cylindersand an eccentric bushing for one of said cylinders rotatively mountedfor movement in one direction to increase impression pressure and in theother to throw off the impression, the combination with the said bushingof an operating mechanismcomprising cooperating hydraulic cylinder andpiston elements defining a working space, a check valve for permittingflow across said piston into the said working space while preventingflow out of said working space, and a spring for applying impressionpressure and acting between said piston and cylinder in a direction toreduce said working space, a crank, means connecting one of the saidhydraulic elements to the bushing and the other to the crank, the crankbeing positioned so as to be on dead center in impression applyingposition, and one of the said connecting means being adjustable forvarying the length of the working space when the crank is on deadcenter, and the References Cited in the file of this patent UNITEDSTATES PATENTS 2,124,420 Kaddeland July 19, 1938 FOREIGN PATENTS 766,519France June 29, 1934

